An analysis of small aperture multimode horn as quasi-optical Gaussian beam radiator

In this paper a small aperture multimode horn is analysed by full-wave method and the coupling efficiency to Gaussian fundamental mode is calculated. The coupling efficiency of exceeding 0.98 is obtained over 4 GHz bandwidth. This horn may be used to connect waveguide with quasi-optical element in millimeter wave system and also may be used as an element in imaging array.     

Phase centers of horn antennas using Gaussian beam mode analysis

The power of Gaussian beam mode analysis to accurately describe the propagation of electromagnetic beams and the location of a horn antenna phase-center is illustrated. By way of example, the case of a compensated pyramidal horn fitted with fins to produce a less abruptly tapered E-plane field distribution is discussed, and the results obtained are compared with those from an alternative method published in the literature. Excellent agreement is found     

Gaussian beam mode analysis of the coupling of power between horn antennas

Gaussian beam mode analysis can be applied in an elegant way to study the coupling of power between two horn antennas. Coupling efficiencies are evaluated for a number of horn combinations and the results presented in a straightforward form useful in the design of submillimetre-wave interferometers and astronomical receiver systems. We show that there is a marked variation in efficiency (up to 30%) depending on the coupling optics, even for beams with well matched profiles.     

An efficient image guide mode launcher

A three section efficient mode launcher for converting TE₁₀ mode of rectangular wave guide to dielectric image guide mode has been designed and tested experimentally. The transmission loss of the trapped image guide and insulated trapped image guide are also evaluated experimentally using this transition.     

Gaussian beam as a bundle of complex rays

It is observed that the function G(P)=eikr/r, where r is the distance from the observation point P to a fixed point having a complex location, represents the field of a Gaussian beam. This can be used to justify, without further computation, the application of formulas of ordinary optics to the transformation of beams through optical systems. It can also be used to solve very simply some problems of diffraction and scattering of Gaussian beams.     

The corrugated horn as an antenna range standard

The corrugated horn discussed here is a valuable tool for use in microwave pattern ranges. It has the properties of concentrated energy in the main beam, low backlobes, high efficiency and almost monotonic amplitude, and phase radiation patterns which make the corrugated horn useful for a source antenna in a pattern range and also as a possible standard antenna for calibration purposes. A sample of the references that have dealt with the corrugated horn is given for the benefit of the reader [1]-[7].     

Corrugated horn radiation analysis using vectorial Gaussian beam expansion out of the balanced hybrid conditions

The beam mode expansion method is adapted to analyze the radiation of a corrugated conical horn without any restriction due to the balanced hybrid conditions, assuming an hybrid modal (HE₁₁)feed. The fields are first calculated on the horn’s aperture and then transformed in a modal expansion. The approximations are discussed and illustrated with computer simulations. Achieved results are finally presented to show the interest of this method.     

Space-time profiles of an ultrashort pulsed Gaussian beam

By using a different initial value from the previous treatments, we reveal that the pulsed Gaussian beam in free space can be expressed as a simple wave packet along with the complex time, which gives all the information about the spatial and temporal behaviors of the pulse. Then the space-time profiles of a space-time Gaussian pulse are studied. It is shown that even when the pulse propagates in free space, there exist couplings among the beam parameters in space and time. The spot-size-related couplings enlarge the temporal domain (TD) spatial size of the pulse and lessen the carrier frequency of the pulse of the paraxial points, and the wavefront-related couplings bend the transverse spatial shape of the pulse with the wavefront     

高斯光束的偏心分布

本文人正常高斯光束的复振幅表达式出发，通过傍轴光波传输公式，得到偏心高斯光束的复振幅和光强分布表达式以及数值模拟光强分布曲线，并与正常高斯光束光强分布的对称性进行了比较。     

A microwave Gaussian-beam launcher with an active aperture-blockageto control the spot-size of the beam

A method of controlling the spot-size of a focused microwave Gaussian-beam using an active aperture-blockage is described. The Gaussian-beam launcher consists of an open-ended scalar-horn with a dielectric hyperhemisphere at its aperture. Also included is an AgI-pellet at the aperture-center with a provision to heat it with an external dc source. The scalar-horn plus the dielectric lens launch a Gaussian-beam; and, the AgI pellet when heated, becomes a superionic conductor offering an aperture-blockage. This results in a variation of the spot-size of the emergent-beam. Theoretical results and experimental data are furnished and compared     

等离子体球对离轴高斯波束的电磁散射

基于高斯波束波形因子的局域近似解和电磁场的球矢量波函数展开方法,研究了离轴高斯波束入射均匀各向异性磁化等离子体球的电磁散射特性.数值计算了波束参数和粒子参数对雷达散射截面(RCS)随散射角分布的影响.分析了改变波束束腰半径和粒子偏离波束轴距离时,RCS的分布特点.结果表明:前向散射截面与束腰半径的变化成正比关系;束腰半径的变化对RCS随散射角分布有很大影响;球粒子偏离波束轴距离的大小影响RCS极值的位置和角分布特点.     

Accuracy of a Gaussian beam

The accuracy of a multimode Gaussian beam is discussed. Novel modifications are given to the conventional Gaussian beam formulation derived using the paraxial approximation. With the modifications, the field can be calculated accurately with the Gaussian beam. Modified multimode Gaussian beam techniques are used for calculation of the beam of a corrugated horn antenna. Phase and amplitude patterns given by this method are compared with measurements and other theoretical methods, namely Huygen's principle and the modal matching technique. The meaning of the phase and phase center is also discussed     

Scattering of an incident Gaussian beam by a perfectly conductingrough surface

The modifications of the regular full wave theory for rough surface scattering by an incident Gaussian beam instead of a plane wave are developed. The Gaussian beam is produced by a large circular aperture that has a Gaussian illumination. It is shown that provided the incident Gaussian beam has a plane phase front over the extent of the rough surface patch and the linear dimensions of the rough patch are large compared with the surface height correlation length, the normalized scattering cross-section is the same as for an incident plane wave     

Simplified high-performance dual-band feed comprising a dual-depth corrugated launcher and a conventional corrugated horn

The design of a corrugated feed is presented which has a simplified configuration in comparison to a feed with dual-depth corrugations over its full length. It exhibits excellent electrical performance which is compatible with the requirements for frequency reuse application in satellite communication antennas. The feed consists of a short dual-depth corrugated launcher and a conventional corrugated horn. Important electrical characteristics of such a feed designated for operation in the standard bands of 4 and 6 GHz satellite communication links are presented.     

Improved radiation pattern performance of Gaussian profiled horn antennas

A new horn antenna profile is presented. This new profile based on Gaussian techniques offers the best solution when the requirements related to the radiation pattern are very stringent. Short-horn antennas with high-conversion efficiency to a fundamental Gaussian beam, and therefore, very low sidelobe and cross-pol levels in a wide-frequency band, could be obtained by using the design technique presented here. Once the theoretical principles of the Gaussian profiled horn antennas (GPHA) are presented, some other possibilities involving Gaussian profiles are studied and compared with their conventional counterparts. Finally, as an example of the design technique proposed, a particular design of a GPHA for HISPASAT 1C and now also valid for the new HISPASAT 1D satellite is presented, showing the excellent agreement between the theoretical and experimental results.     

高斯激光束通过自聚焦微透镜的聚焦

本文使用矩阵光学方法，对高斯激光束通过自聚焦微透镜的聚焦问题作了详细讨论，本文给出了其束腰间的一般变换公式，讨论了象方束腰随物方束腰位置的变化规律，并且研究了几种典型节距的自聚焦微透镜的聚焦问题。     

Gaussian beam transformation with cylindrical lenses

We develop formulas for Gaussian beam transformation with fixed total distance between beamwaists, and consider the use of cylindrical lenses or mirrors to produce beams which are not symmetric about the axis of propagation. For antenna feeds, it is necessary that the beam waists for both planes perpendicular to the axis of propagation be coincident. This requirement is analyzed, and appropriate transformation formulas obtained. The far-field patterns of a scalar feed born cylindrical lens combination operating at a frequency of 94 GHz have been measured and found to be in quite good agreement with the elliptical patterns predicted by the transformation formulas.     

高斯光束通过光阑——透镜分离系统的焦移

本文根据Ｃｏｌｌｉｎｓ衍射积分公式分析了高斯光束通过光阑－－透镜分离系统后的焦移情况，得到在不同的分离状况下，其焦移可能反向或被消除，对它的两种极限情况也做了分析。     

A note on the coupling efficiency between an antenna and a Gaussian beam

In this communication a note on the coupling efficiency between an antenna and a Gaussian beam is presented. The calculations of the coupling efficiency from both methods, a nomorlized inner product between the antenna radiation pattern and the Gaussian-beam pattern or alternatively, between the electric field at the antenna aperture and a two-dimensional field representation of a Gaussian beam, are compared for different aperture size in wavelength. How a correct solution can be gotten is stated.     

Electromagnetic Gaussian beam beyond the paraxial regime

A modified electromagnetic beam technique is derived analytically from the asymptotic field expressions for the quasi-optical, millimeter-wave, plane polarized Laguerre-Gaussian modes of arbitrary order. The method makes use of the paraxial-wave formulas only, yet it accurately gives the full electric field vector at any point far beyond the conventional Gaussian beam regime. The technique is assessed numerically against the exact Green's function results